Well perforation cleaning tool



1964 v. H. CALDWELL WELL PERFORATION CLEANING TOOL Filed Sept. 11, 1961 l l l INVENTOR M w am y United States Patent 5,163,227 WELL PERFGRATION CLEANING TOOL Verdie H. Caldwell, 1094 Woodrow Ave., Oildale, Cahf. Filed Sept. 11, 1%1, Ser. No. 137,123 4 Claims. (Cl. 166-462) This invention relates to a tool for use in cleaning out wells, mainly oilwells, and in particular it relates to the cleaning out of the perforations in the liners or screens; Perforated liners and/or screens vary in design and a typical liner or screen is perforated with shot-holes made therein by suitable well completing tools. In the drawings I have shown the present invention as it is applied to cleaning of shofihole perforations, it being understood that other types of liners and screens can be cleaned thereby without deviating from said invention.

A producing well must be cleaned out from time to time and for various reasons. Sand ordinarily enters into the lower portion of the well and packs around the pumping string, and formation packs into the perforations clogging the same. Cleaning out is generally accomplished by using a sand-pump and/or bailer. The sandpump is a device that has a sucker valve with a plunger, so that when it is lowered to the bottom of the hole and the plunger is pulled up, the mixture in the well is drawn into the pump, which is then raised to the surface by a reel and sand-line and then dumped. The bailer is simply a long tube with a dart-valve in the bottom, and when it is lowered to the bottom of the hole the dart strikes and opens the valve, thus admitting mixture into the tool. When the bailer is drawn up the valve closes and the fluid is retained in the tube until it reaches the surface, whereupon the tube is emptied by striking the dart for discharge of the pumpings. These two well tools are used in cleaning both new and old wells and they require lowering and raising into and from the well, and for each complete lowering and raising operation they remove a load of material from the well.

The cleaning operation performed by either of the above mentioned tools is time consuming and is often accompanied by cleaning out of the perforations in the liner or screen. For example, a separate and distinct tool is ordinarily lowered 'to the vicinity of the perforations and reciprocated a number of times and over a length of time sufiicient to have entered and cleaned the perforations. These tools are ordinarily of considerable length and do not, therefore, permit themselves to be combined with other lengthy tools such as sand-pumps and/ or bailers. For example, a usual perforation cleaning tool is eighteen to twenty feet in vertical extent and this is also the usual length of a sand-pump or bailer. In any case, the combination of two such tools is too lengthy and much too cumbersome to be practical. However, it is feasible to employ a perforation cleaning tool in conjunction with a sand-pump or bailer, since the latter are. usually lowered into and raised from a well a number of. times in the process of cleaning the same, said raising and lowering is advantageously used to operate the perforation cleaner hereinafter disclosed.

An object of this invention is to provide a perfora tion cleaner for use in cleaning Well liners and/or screens and'which can be operated in conjunction with sand-pumps and/or'bailers and the like.

'such as a sand-pump and/ or bailer or the like.

"ice

It is also an object of this invention to provide a clean ing wheel in a tool of the character under consideration and that is adapted to properly and adequately clean throughout which description reference is made to the accompanying drawings, in which: 7

, FIG. 1 is an elevation of the perforation cleaning tool of the present invention.

FIG. 2 is a plan section, enlarged and taken as indicated by line 22 on FIG. 1.

FIG. 3 is an enlarged detailed sectional view of a portion of the structure and taken as indicated by line 3 on FIG. 2.

FIG. 4 is a fragmentary view of a portion ofthe structure as shown in FIG. 3 and showing the rotation of the wheel thereof.

The perforation cleaning tool T that I provide is adapted to clean perforations in the liners or screens of a well, particularly on oilwells, and in the drawings I have shown the preferred form of the invention which is adapted to clean shot-hole perforations. The well is charactertized by a liner or screen 1% with shot-holes 11 through the wall thereof, for example six vertically disposed rows of shot-holes 11. The said shot-holes are produced in the conventional manner as by using perforating guns, and they are therefore formed by a piercing method which upsets the wall radially outward as shown. The tool T is adapted to berun into the well in conjunction with a sand-pump or bailer B and it is connected directly with said bailer B. Furthermore, it is contemplated that the tool T comprises a body forming a bailer or a portion of a bailer. As clearly illustrated, the tool T involves, generally, a body A, one or more hole cleaning means C, and a dart operated valve V. In accordance with the invention it is desired to accomplish more work than is possible with a single cleaning means C and therefore a plurality of means C is employed, but without excessively lengthening the tool.

The body A is a tubular part having an imperforate side wall 12 and with a coupling 13 at the uppermost end thereof. The body A is normally disposed vertically, as

shown, and the top is opened into the bottom of the well or into a sand-pump'or bailer B, as circumstances require. It is to be understood that the sand-pump or bai er B can operate independently from the tool T, or as is preferred, the body A forms a continuation of the bailer tube, in which case the dart operated valve V is positioned at the lowermost end of the tool T. The coupling 13 is indicated as a usual threaded joint whereby the top'end of the tool T is joined to the lower end of the bailer B. Thus,'the bailer B is operable in itself or in an upward continuation of the tubular body side wall 12.

The dart operated valve V is shown carried in the lower end of the body A, and it is a downwardly shutting valve thatis adapted to support a column of fluid within the tubular body. The valve V is opened by a depending dart 15 that projects beneath thetool T to engage the bottom of therwell hole, whereby-the valve element 16 is' lifted from the, seat 17. Thus,,the valve V opens and closes the body A so that the tool T operates as a bailer. Further, the body A can also be employed with a sand-pump (not shown) wherein a piston is employed to suck fluid into the tools.

The hole cleaning means C is provided to clean out the shot-hole perforations 11 by entering thereimand there is provided a plurality of like units each forming a complete means C. In accordance with the invention it is the relationship of these units relative to each other which FIG. 4).

that I contemplate providing.

materially shortens the vertical length of the tool I, whereby the tool T is man height or about six feet 111 height. Since shot-holes and like perforations are usually spaced circumferentially ineven divisions such as twofour and six, I employ an odd number of means C, for example seven of said means. With this specified number of means C, each of said means occupies a greater circum'ference of the body A than its fractional share of with the result that circumferential overlapping must be provided for (see FIG. 2). Notice that said overlapping of the means C occurs internally of the body A. In order to clearly explain my novel relationship thereof I will refer to these seven means as being numbered 1 through 7 as indicated in the drawing as they occur in stepped relationship circumferentially spaced around the body A. As shown, every other one of said means, is

stepped downward from the preceding one a distance of approximately one-half the height of a'unit or means C. In practice, .thesaid means canbe stepped closer than onehalf the said height, as is clearly shown. As 'a result, said overlapping is permitted and the overall height of the tool T is minimized withouteliminating any or reducing the number of means C.

Each means C is a perforation cleaning means or unit and .a description of one of said means will suffice for all. As shown, the means'C involves, generally, a wheel 20, a

a 4 ments, the said elements are bound at their free ends by a slide 26'. p

A feature of the presentinvention is the mounting 30 that accommodates the carrier 25. As pointed out above, the wall 12 of the body A is imperforate and the mounting or mountings 30 establish recesses therein opening only from the outside of the tubular part. Each mount- 1 ing is a longitudinally disposed channel 31 having oppocarrier 25 for supporting the wheel, and a mounting V for the carrier. The mounting 30 is built into the wall 12 of the body A and the carrier is accommodated in the mounting 30 and projects therefrom in order to press the wheel v20 into engagement with the liner or screen 10.

The wheel 29 is generally the shape of a star, or the like, being made of a flat plate and characterized by pairs of circumferentially adjacent points 21. The points 21 are spaced circumferentially of the wheel and each has a pair of angularly related faces 22 that form a vertex. The faces 22 of adjacent points are opposed and in a common plane whereby they can have flat sliding engagement with the liner it) (see FIG. 3). As shown, a practical Wheel 20-has four points and when a shot-hole perforation is encountered thereby, the advancing point 21. drops or slides'into the hole whereupon the wheel 20 turns (see As shown, the points 21 are tapered'as they project radially, having slightly convergent sides 22'. In practice, the wheel is characterized by flat edges normal to the opposite flat faces thereof, however it is also anticipated that rounded pin-like tooth points are feasible. Turning of the wheel 20 results in a prying action of the point 21, said point being of smaller configuration than the hole to be cleared, so that cloggings are effectively. removed from the shot-hole. It isto be understood that the same wheel can be constructed with three or five points, or any other number, for example, and without destroying the circumferentially paired relationship of points 21 The carrier 25' for supporting the wheel 26 carries said wheel on a transverse axis horizontally-disposed, and removed laterally from the central vertical axis of the tool T. The carrier 25 is provided topermit radial shifting of the wheel Hand to yieldingly urge said'wheel into pressured engagement with the liner. 1t). As shown, the carrier25 is in the form of a belly spring 26," anchored at one end by means of a fastener 27 and shiftably restrained 'ment one with'the,v other, one of which islongitudinally site side Walls 32, a bottom 33 and ends 34 and 35. The said parts 32,- 33, 34 and 35 ,are joined together, as is shown, and the spring elements 26 are anchored to the bottom 33 at one end while the slide means 28 is carried between the walls32 at the other end. As a result, it is feasible, if so desired, for the carrier 25 and wheel- 20 to be received within the confines of the channel 31 if and when such retraction'isnecessary due to restrictions in the well hole. I,

From the foregoing it will be apparent that the tool T that I provide is extremely compact and composite in nature, as it is characterized by the stepped and overlapped hole cleaning means C. The saidmeans-C are retractably' accommodated within the diameter of the body A without perforation of the wall 12 thereof and all to the end that the tool T can be employed in conjunction with a sand-pump or bailer.. Furthermore, the perforation cleaning wheels are highly effective in servicing shot-hole perforations which are otherwise very difficult to clean.

' When vertically disposed upon a derrick floor it is possible for a man to reach the top of the tool with facility and to perform any operations that may be necessary at the said position. Furthermore, with the valve V as disclosed at the lowermost end of the tubular body A it is possible to employ the tool T also as or in combination with a sandpump or bailer, or with any like orequivalent well too]. Having described only a typical preferred form and application of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any modifications or variations that may appear to those skilled in the art and fall within the scope of the following claims. Having described my invention, I claim:

1. A tool for cleaning perforations in a well liner and 7 including, an elongate body for insertion into and through said well liner, and perforationcleaning means comprising a belly spring anchored to the body and a star shaped wheel carried on a pin by said spring and having points to enter into the perforations, said spring comprising inner and outer leaves anchored at the ends of the spring and in fiat adjacent-engagement throughout their lengths anchored to the body and a star shaped wheel carried by. said spring and having points to enter into the perforations,-said cleaning means comprising channels recessed in the body to accommodate the springs and in overlapped circumferential positions relative to each other and the channel of every other one of said cleaning means bemg stepped approximately one-half itsheight lower than 7 said preceding higherone.

slotted at 24 to pass the wheel-20 and the'other which is bent at '23 to form a transverse bearing. It is the inner most spring element that forms the bearing at '23 and which presses the wheel pith-2t) outwardly. In order to permit full freedom Off movement, of thetwo spring ele- 3. A toolfforcleaning perforations in awell liner and including, an elongate-body for insertion into and through said well-liner, at least several pairs of like perforation cleaning means and each comprising a belly spring anchored: to the body and a star shaped wheel carried bysaidspring and having points to enter into the perfora tions, said cleaning means comprising channelsrecessed in the body to' accommodate the springs and in overlapped -circurn ferential positions relative to each other,

4. A tool for removing fluid from a well and for simultaneously cleaning perforations in the liner of said Well and including, an elon ate tubular body with an imperforate wall, at least several pairs of like perforation cleaning means and each comprising a bellyspring anchored to the body and a star shaped wheel carried by the said spring and having points to enter into perforations, said cleaning means comprising channels recessed in the body to accommodate the springs and in overlapped circumferential positions relative to each other, and the channel of every other one of said cleaning means being stepped ap proximately one-half its height lower than said preceding higher one, and a dart operated valve at the lower end of the body to admit fluid from the well upon engagement with the Well hole bottom.

References Cited in the file of this patent UNITED STATES PATENTS 1,342,618 Bashara June 3, 1920 1,380,517 Bashara Jnne 7, 1921 1,426,305 McDonell et al. Aug. 15, 1922 1,525,602 Barton Feb. 10, 1925 1,806,073 MacGregor et a1 May 19, 1931 2,151,416 Black et a1 Mar. 21, 1939 2,212,784 McCune Aug. 27, 1940 2,298,985 Still et al. Oct. 13, 1942 2,574,141 Brown Nov. 6, 1951 

1. A TOOL FOR CLEANING PERFORATIONS IN A WELL LINER AND INCLUDING, AN ELONGATED BODY FOR INSERTION INTO AND THROUGH SAID WELL LINER, AND PERFORATION CLEANING MEANS COMPRISING A BELLY SPRING ANCHORED TO THE BODY AND A STAR SHAPED WHEEL CARRIED ON A PIN BY SAID SPRING AND HAVING POINTS TO ENTER INTO THE PERFORATIONS, SAID SPRING COMPRISING INNER AND OUTER LEAVES ANCHORED AT THE ENDS OF THE SPRING AND IN FLAT ADJACENT ENGAGEMENT THROUGHOUT THEIR LENGTHS AND EACH SLOTTED TO PASS THE WHEEL, AND ONE LEAF WITH A BEARING OPPOSED TO THE OTHER LEAF IN ORDER TO SUPPORT AND POSITION THE PIN CARRYING THE WHEEL. 